Circuit breaker



June 20, 1939..

Filed Oct. 9, 1936 8' 53 1 I 56% W TL BY X' JJ M 3 Sheets-Sheet 1 I h! I at if 51 :2

INVENTOR. MESH'BLUEILSI' a g ATTORNEYS June 20, 1939. Y J; H. BURNYSIDE. 2D

C IRCUIT BREAKER Filed Oct. 9, 1936 3 Sheets-Sheet INVENTOR.

A? ATTORNEYS 4 June 20, 1939. J. H. BURNSIDE. 2p

CIRCUIT BREAKER 3 Sheets-Sheet 3 Filed Oct. 9, 1936 1N VENTOR. Jamesfl bmm'zdgfmi BY MW? HIS ATTORNEYS Patented June 20, 1939 UNITED STATES PATENT GFFICE 2,162,935 CIRCUIT BREAKER James H. Burnside, 2d, New York, N. Y., assignor, by mesne assignments, to Circuit Breakers, Inc-., New York, N. Y., a corporation of New York This invention relates to small circuit breakers and particularly to that type of breaker known commercially as branch circuit breakers which provide protective features similar to a fuse but have the added advantage of being a manually operated switch as well. In the past, a number of small circuit breakers have been provided with thermal release arrangements to open the breaker upon the existence of an overload. However, N there is still much to be desired in such breakers which have heretofore been proposed to replace fuses. Since branch circuit breakers, as applied in practice to panel boards for the protection of lighting and motor circuits are called upon to in- 15 terrupt currents of very large amounts compared to the rating of the breaker (in numerous instances more than ten times the normal rating of the breaker), the ability of the device to continuously interrupt such large currents is one 30 of the primary requisites of a commercially successful device. 1

In addition to the foregoing, it is also necessary that such breakers, if they are to be truly interchangeable with' fuses, be of such dimension that they can be inserted in the standard cut-out boxes and panel boards encountered in modern commercial practice. When considering plug type breakers for use in standard Edison screw base fixtures, a limitation of physical dimension is encountered whereby the maximum permissible diameter or width must not exceed 1.4 inches and the maximum overall height must not exceed 1% inches. It is therefore apparent that to attempt the interruption of such large currents in such a small space presents a problem, which has as yetnot been successfully solved.

An object of the invention, accordingly, is to provide an improved branch type circuit breaker which is adapted to be used as a manually operm ated switch, wherein, within the space available in standard cut-out boxes and panel boards an effective mechanism is provided for performing the operations to which it is subjected.

A further object of the invention is to provide,

43 in a breaker of the above character, a structure which is relatively inexpensive and yet which is rugged and able to withstand the severe stresses to which it is subjected in operation. In'this connection, the invention provides a construction 50 wherein a relatively long are path is provided by utilizing a circular motion, the construction being such as to prevent the jumping of the are across the space between the extremities of the circular motion.

55 The invention further contemplates the provision of a free tripping mechanism which prevents holding the breaker in a closed position during the existence of a short circuit or overload on the line.

Other advantages, in addition to the ones above specifically recited, will be apparent as the de-- scription of the invention proceeds.

It will be apparent that to be commercially practical the cost of such a breaker must necessarily not exceed by too wide a margin the cost of a'fuse. There is therefore an additional limitation as to the cost of materials which may be ermployed in the manufacture of such a device. In the description to follow, it is set forth how the foregoing requirements have been met.

First of all, the particulardesign employing a rotary motion has been resorted to in order to obtain the greatest possible separation between the opening contacts in the space available and also means have been provided to open these contacts as rapidly as possible. Since blow-out coils and such other means of deionizing the arcing space are impractical in the space available and because of the cost of the same, the foregoing provides a simple and efficient means of extinguishing the arc. It should be pointed out that the arc, when a very large current'is being interrupted, follows the brush around the circumference of the rotor rather than cutting across the top or bottom thereof, resulting in a greater distance through air for the are. In addition, the resistance of the arc is further increased by the design and action of the brush holder which is composed of an insulating material having a high fusing point, being so positioned that it acts similarly to a shutter or barrier between the contacts. Moreover, the wiping action of the brush and shutter against the outer casing efiectively eliminates the collecting of metal vapor upon the contacts where it would otherwise tend to collect and harden with a resulting impairment of the operation of the mechanism.

In order that the invention may be described more fully, reference will now be had to the accompanying drawings, wherein Figure 1 is a view in. vertical section taken through the axis of a device constructed in accordance with the present invention. The section upon which this figure is taken is iliustrated I by the line 1-! in Figure 2;

Figure 2 is a top plan view of Figure 1 with the cover removed and showing the rotor partially in section;

Figure 3 is a view in section, taken on line it-tbf Figure 2, and looking in the direction of the arrows;

Figure 4 is a view similar to Figure 2, showing the manner in which the contacts are released manually, this view being taken in section on the line 6- 3 of Figure 1 and looking in the direction of the arrows; v

Figure is a view similar to Figure 3, showing the elements of Figure 4 in the released poments shownin Figure 4 and looking from the position as shown in Figure 10.

left with the casing removed;

Figure 8 is a view' in section, taken on the line 8-8 of Figure 2 and looking in the direction of the arrows; c

Figure 9 is a view in section, taken on the line t of Figure 1 and looking in'the direction of the arrows;

Figure 10 is a view similar to Figures 5 and 6, showing the mechanism in an open position.

With reference to the above drawings, the device is shown as being formed with a housing ill having an extension it formed thereon, upon which a threaded shell member 02 is provided.

A central contact 83 is mounted upon the bottom of the extension 9 l and is conmcted to an inner platform It, provided with an upwardly extending pedestal 15. A bearing I B is provided with an inwardly extending recessed member H which is received over the pedestal i5, the bearing forming an annular bearing space within which the lower extremity of a shaft lt'is received. Shaft i8 is formed with a slot it within which one end of a coiled spring is secured, the other end of the spring being secured to the extension H of the casing ill, as shown at 2i in Figure 9.

Upon the upper end of the shaft i8 is secured a cylindrical rotor 22, formed with an inwardly extending recess 23 which communicates with the peripheral surface thereof. Thisrecess receives a. sleeve 24,.formed of insulating material. and within sleeve 24 is provided a metallic brush 25 having an inserted carbon or graphite piece 25' on one side which serves as the movable p shaft l8 (of current conductive material) through a pigtail 28 which is connected at one end to the brush 25, and at its other end to a post 29, secured to a bi-metaliic strip or band 30 adjacent one end thereof. The other end of the bi-metallic band 30 is secured to the rotor 22 by means of a screw 3|, the bi-metallic element 30 being received within a recess 32, formed in the lower side of the rotor 22. The bi-metallic member 319 is formed with an arm 33 which is secured to the shaft l8 at 34. In this fashion, current flows from the central contact terminal i3 through the platform H, pedesdownwardly extending/contact strip 36 to engage the threaded shell l2, thus completing the giddfidh circuit. Contact member is provided with a portion 3? of carbon or graphite to'resist arcing when the contacts open. v

The casing it is provided with a shoulder 38 which is adapted to be engaged by a pin 3% slidably mounted in the rotor 22 and urged clownwardly bye. spring dd. This pin. is formed with flange M which isadaptedto be engaged by the end of the'bi-metallic element 30. When current flowing through thedevlce exceeds a predetermined maximum, the heat generated in the lei-metallic element it causes the same to flex upwardly and release. the pin 39 from the shoulder 38. This meleeses the rotor 22 and permits the spring 26 to return the same to the open fdotlon of the rotor 22 is limited by a shoulder 52 which is received within an annularly recessed or reduced portion 63 which, in the construction shown, extends substantially through half the circumference of the rotor 22.- Such annular recess terminates in shoulders td and 65, against whichthe lug 62 abuts when the rotor is in the closed and open positions respectively. The closed position or the rotor is shown in Figure 2, wherein the shoulder 44 isabutting against the lug 42, whereas the-open position is illustrated in Figure 10 wherein the shoulder 45 is abutting against the lug 42. In order to increase the speed of the rotor during the initial circuit breaking movement an auxiliary spring 38 is provided within a recess 41, formed within ,the rotor 22. This spring abuts against the lug A2 and normally urges the rotor into an open position. After the rotor has been moved into an open position such that the contacts 25 and 85 have been separated, spring 46 no longer functions, and further opening motion of the rotor journaled within a cover 50 which is suitably secured to the housing It. Shaft 49 extends within the housing and is located within a shaft sec-' tion 5i which is journaled within a recess 52, formed within the rotor 22. Between the shaft sections 49 and ii, a radially extending arm 63 is received, the am being formed with a flat surface 54 to engage a cooperating flat surface formed on the extremity of shaft 49. In this fashion, motion of the handle 48 is transmitted to the arm 53. A spring 55 is secured to the arm 53 and rotor 22, this spring urging the arm 53 into& circuit opening position.

Arm 53 is formed with a downwardlyextend ing detent E6 which is adapted to engage a recess 51 formed in the rotor 22, thus enabling the motion of the handle 48 to be transmitted to the rotor in order that the latter may be moved into a circuit closing position. The extremity of arm 53 is also provided with a projection 58 which is adapted to engage an upwardlyextendmg cam surface 59 formed upon the lug 42. ,When the pin 39 engages the shoulder 38, the extension 58 rides up on the cam 59 and elevates the detent 58 from the recess 51, thus preventing the rotor from being held in a closed position manually.

' In order that the circuit may be closed after the rotor has been moved into such position that the stationary and movable contacts are in alignment, the sleeve 24 and contact 25 are formed with a recess 60 in which a catch ii is adapted to engage. The catch 6| is formed upon a catch lever which is pivoted at 62 in the rotor. The end of the catch lever is formed with an upwardly extending arm 53 against which a spring 64 may engage to urge the catch against the sleeve 24. The arm 83 extends upwardly suinciently far to be engagedby the arm 53 in order i rotor and movable contact are moved into the normally open position illustrated in Figure 10, the movable contact is moved into a retracted position by means of a cam 65, formed in the casing 50. A cam 22 is provided on the rotor 22 to permit the arm 53 to move into its normal position and over the upper extremity of arm 63 after a free tripping operation has occurred.

In order that the contacts may be released manually, the arm 53 is formed with an arm 66, the end of which is provided with a cam surface 67 which is adapted to engage beneath a button 68, formed on the pin 39. Upon manual motion of the control member 48 in a COUIllLEZClOCkWiTt-E direction, as viewed in Figure 2, the cam surface 61 engages beneath the button 68 and elevates the pin 39 as illustrated in Figure 5. This provides a convenient and effective manual releasing mechanism for the device.

As the contacts 25 and break by reason of the existence of a predetermined excess current, arcing will occur. The duration of this arcing will depend upon the amount of current flowing and the speed with which the contacts separa e. By providing an insert in the brush 25 of carbon or similar material which does not deteriorate as readily under an are as the softer metals,-the effective life of the breaker is greatly increased. Moreover, the sleeve 24 assists in reduc ng the arcing and protects the edges of the contacts by reducing, to a minimum, the space between the two contacts through which space the arc must pass.

I claim:

1. A circuit breaker comprising stationary and movable contacts, means to urge the movable contact normally into an open position, bi-metal controlled means to hold the movable contact in closed position, actuating means to move the movable contact from an open circuit position,

means to render the actuating means inoperative, and means to subsequently close the contacts by the actuating means.

2. A circuit breaker comprising stationary and movable contacts, means to urge the movable contact normally into an open position, bi-metal controlled means to hold the movable contact in closed position, actuating means to move the movable contact from an open circuit position, means to render the actuating means inoperative, and means to subsequently close the contacts'by continued motion of the actuating means.

3. A circuit breaker comprising stationary and movable contacts, means to urge the movable contact normally into an open position, bi-metal controlled means to hold the movable contact in closed position, actuating means to move the movable contact from an open circuit position, means operable upon motion of the movable contact and actuating means into open position to hold the movable contact in a retracted position,

J'ournaled and means to release the movable contact after the actuating means has moved the movable contact adjacent the circuit closing position.

4. A circuit breaker comprisingstationary and movable contacts, means to urge the movable contact normally into an open position, bi-met-al controlled means to hold the movable contact in closed position, actuating means to move the movable contact into a circuit closing position, a catch operable upon motion of the movable contact and actuating means into open position to hold the movable contact in a retracted position, means to render the actuating meansinoperative, and means actuated by the actuating means to release the catch after the actuating means has been rendered inoperative.

5. A circuit breaker comprising stationary and,

movable contacts, means to urge the movable contact normally into an open position, bi-metal controlled means. to hold the movable contact in closed position, actuating means to move the movable contact into a circuit closing position, a catch operable upon motion of the movable contact and actuating means into open position to hold the movable contact in a retracted position, means to render the actuating means inoperative, means to move the movable contact to a retracted position upon movement thereof into the normal open position, and means actuated by the actuating means to release the catch after ghe actuating means has been rendered inopera- 6. A circuit breaker comprising a stationary contact, a rotor, said rotor having a circularly curved peripheral surface and transverse ends meeting the peripheral portion in sharp edges to form are resisting paths, a contact carried by the rotor and positioned in the curved surface intermediate the edges thereof and spaced from the planes of the transverse ends, the arcuate path of travel of the movable contact being shorter than the straight line arcing path on the transverse ends and on the curved surface axially of the rotor during the initial circuit breaking motion and greater than such straight line path during the final breaking motion, means to urge the rotor normally into an open position, bi-metal controlled means to hold the rotor in a closed position, operating means for the rotor, and means to render the operating the rotor is in a closed position.

7. A circuit breaker comprising a casing in which a stationary contact is mounted, a rotor journaled in the casing, a contact movably mounted on the rotor, means to urge the last named contact outwardly, means to urge the rotor into an open position, and bi-metal means to release the rotor.

t. A circuit breaker comprising a casing in which a stationary .contact is mounted, a rotor in the casing, a contact movably mounted on the rotor, means to urge the last named contact outwardly, an insulating sleeve slidably mounted on the last named contact, means to urge the rotor into an open position, and bi-metal means to release the rotor.

9. A circuit breaker comprising a casing in which a stationary contact is mounted, a rotor journaled in the casing and having a contact mounted thereon adapted to cooperate with the first contact, means to urge the rotor into an open position, bi-metal means to release the rotor, an elongated peripheral groove in the rotor, and a projection in the casing to engage the groove and limit the rotation of the rotor.

means inoperative when I a i 10. A circuit breaker comprising a casing in which a stationary contact is mounted, a rotor journaled in the casing and having a contact mounted thereon adapted to cooperate with the first contact, means to urge the rotor into an open position, bi-metal means to release the rotor, an elongated peripheral groove in the rotor, a projection in the casing to engage the groove and limit the rotation of the rotor, a manual connection to actuate the rotor, and means on the projection to render the last named cennection inoperative.

11. Acircuit breaker comprising a casing in which a stationary contact is mounted, a rotor contact normally into an open position, the opening of the contacts taking place with a wiping action, bi-metal controlled means to hold the contacts in closed position, and segments of arcresisting material associated with the contacts and mounted to remain in contact after the first contacts have opened.

13. A circuit breakercomprising stationary and movable contacts, means to urge the movable contact normally'into an open position, the opening of the contacts taking place with a Wiping action, bi-metal controlled means to hold thecontacts in closed position, segments of arc-resisting material associated with the contacts and mounted to remain in contact after the first contacts have opened, and an insulating sleeve'slidably mounted on the movable contact to extinguish arcs tending to form upon opening of the contacts.

14. A circuit breaker comprising a casing having a. chamber formed therein with a curved inner surface, a fixed contact formed in the wall of the chamber and lying flush with the inner surface of the chamber, a rotor journaled in the casing and having at least a-portion of the peripheral surface thereof formed about a radius substantially the same as the distance of the inner surface of the chamber and the contact surface of the fixed contact from the axis of the rotor, a contact on the rotor adapted to engage the fixed contact and mounted in the peripheral surface, movements of the rotor effecting relative movement between the said contacts on an,

arcuate path, means to urge the rotor into contact disengaging position, means for holding the rotor in contact engaging position, and means for releasing the holding means upon the development of an overload in a circuit .in breaker is connected. 1

15. A circuit breaker comprising a casing having a chamber formed therein with a curved inner surface, a fixed contact formed in the wall of the chamber and lying flush with the inner surface of the c amber, asrotor journaled in the casing and ha ng at least a portion of the peripheral surface thereof formed about a radius substantiallyth'e same as the distance of the inner surface of the chamberand the contact surface of aieaese connected.

i6. A circuit breaker comprising a casing having a chamber formed therein with a. curved inner surface, a fixed contact formed in the Wall of the chamber and lying flush with the inner surface of the chamber, a rotor journaled in the casing and having at least a portion of. the peripheral surface thereof formed about a radius substantially the same as the distance of the inner surface of the chamber and the contact surface of the fixed contact from the axis of the rotor, a contact on the rotor adapted to engage the fixed contact and mounted in the peripheral surface, movements of the rotor efiecting relative movement between the said contacts on an arcuate path, means to urge the rotor into contact the holding means upon the development of an .overload in a circuit in which the circuit breaker is connected.

17. A circuit breaker comprising a casing, a rotatable contact carrying member in the casing,

means to urge the member normally into an open position, releasable means to hold the member in a circuit closing position, a manually operable member, engaging means between the manual member .and the rotatable member, and means to release the releasable means bythe manual member.

which the circuit 18. A circuit breaker comprising a stationary contact, a rotor, said rotor having a circularly curved peripheral surface and transverse ends transverse ends and on the curved surface axially of therotor during the initial circuit breaking motion and greater than. such straight line path during the final breaking motion, means to urge the rotor normally into an open position, bi-metal closed means to hold the rotor in a' closed position and operating means for the rotor.

219. A circuit breaker comprising a casing;.a rotor journaled in the casing, a fixed contact on the casing, a contact on the rotor; movements of the rotor effecting relative movement between the contacts on an arcuate path about the longitudinal axis of the casing, the rotor contact sliding along the casing wall during movement of the rotor, means for urging the rotor to contact disengaging position, means for holding the rotor; in contact engaging position, and heat respon 

